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T. G. MARTIN. MEASURED SERVICE TELEPHONE SYSTEM. arwcmou nun AUG-B, m2. upnivlw we. 31

Patented Aug. 12, 1919.

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T. G. MARTlN.

MEASURED SERVICE TELEPHONE SYSTEM. APPLICATION FILED AUG-8,1912- RENEWED AUG. 3| ISIE- 1 ,3 1 2,702 Patented Aug. 12, 1919.

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T. G. MARTiN.

MEASURED SERVICE TELEPHONE SYSTEM.

APPLICATION man was. 1912. RENEWED AUG. 31.1913.

1 ,3 1 2,702. Patented Aug. 12, 1919.

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UNITED STATES PATENT OFFICE.

TALBOT G. MARTIN, OF CHICAGO, ILLINOIS, ASSIGNOR T0 AUTOMATIC ELECTRIC COMPANY, OF .GHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

MEASURED-SERVICE TELEPHONE SYSTEM.

Application filed August 8, 1912, Serial No. 713,957.

To all to ham it may concern:

Be it known that I, TALBOT G. Mamas, a citizen of the United States, and resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Measured-Jervice Telephone Systems, of which the following is a specification.

My invention relates to semi-automatic telephone systems, and more particularly to improved means for registering calls in suvh systems.

Among the objects of my invention are to provide in a semi-automatic telephone system a meter for the calling subscribers line which is automatically operated to reg ister the call upon the response of the called subscriber.

A more specific object of my invention is to provide for this automatic operation of the meter in a semi-automatic system in which the calling subscriber obtains connection with the manual switchboard through a plurality of trunking switches.

A further novel feature of my invention is the manner in which the meter is operated by a stengthened impulse, which impulse is strengthened to operate the meter automatically upon the response of the called subscriber.

These and other objects of my invention will be more readily understood by reference to the accompanying drawings, in which I have illustrated a semi-automatic system in which the features of my inventlon are embodied.

In the accompanying drawings Figures 1 and 2 taken together show a. complete connection between a calling substation A and a called substation A in a system embodying the principles of my invention.

Figs. 3 and 4 represent a connection between a calling substation A and a called substation A in a system similar to that represented in Figs. 1 and 2, but employing slightly different circuit arrangements.

The telephone system represented herein is of that type in which the connections between the calling and called subscribers are completed manually by an operator, but in which the subscribers lines do not have individual answering terminals at the central office, the answering terminals being common to all the lines, and each line being Specification of Letters Patent.

Renewed August 31, 1918. Serial No. 252,258.

provided with apparatus for automatically connecting it with an idle answering termi nal upon the initiation of a call. For instance: Referring to Fig. 1, the line of the substation A is equipped with one or more multiple jacks J at the central office in the usual manner, but instead of the usual answering jack, said line is provided with an automatic trunk-selecting switch C. This automatic switch C, together with a number of other similar switches, has access to a common group of trunk lines, each of which leads to a so-called secondary trunk-select ing switch C. Like the subscribers individual switches, the secondary switches are also divided into groups, each group of switches having access to a common group of trunk lines each of which leads to an operators cord circuit 0 which terminates in a plug P (Fig. :2). The trunk lines leading from each group of subscribers primary switches C are uniformly distributed among the various groups of secondary switches C and the trunk lines leading from each group of secondary switches C are distributed among the various operators positions on the manual board. With this arrangement the answering terminals on the manual switchboard may all be made common to all the substations in the exchange, and the calls from the various substations will be distributed among the dilferent operators. Any subscriber wishing to make a call simply removes his receiver from the switch hook, whereupon the switches C and C automatically operate to extend his line to an idle plug P and to signal the operator. The operator completes the connection by inserting the plug P into the multiple jack of the line called for in the usual manner.

The substations shown herein may be of any suitable common battery type. Referring to the substation A, the substations shown herein comprise the usual receiver 2, transmitter 3, switch hook 4, ringer 5 and. condenser 6.

The rimary and secondary trunk-selecting switches C and C are of the general type of switches disclosed in the Western Electrician of Chicago, Illinois, of January 25, 1908, being of the particular type, however, shown in British patent to A. E. Keith, N0. 1421 of 1910. These line switches, as is well known, are each pro Vided with a plunger which, when idle, is

always maintained opposite the bank ter minal of an idle trunk line by a so-called master switch, and upon the operation of said switch its plunger is forced into the bank of said idle trunk line to connect the line leading to it with said trunk. The master switches shown herein are somewhat different from those shown in said British Patent No. 1421 of .1910. Referring to the master switch D (Fig. 1), 18 is the usual plunger shaft through the medium of which the master switch controls the plungers of the trunloselecting switches. The plunger shaft 18 is connected with a rotary shaft 19 in such a manner that, as the shaft 19 is rotated back and forth, the plunger shaft 18 is caused to oscillate about said shaft 19 as an axis. The shaft 19 is adapted to be rotated in one direction by a spring 20 and in the other direction against the tension of said sprin by a. solenoid 21. Secured to the shaft il there is a cam member 22 provided along its outer edge with a series of notches 23. one for each trunk line to which the line switches have access. The shaft 19 is normally locked against rotation in either direction by the engagement of the lever 24 with one of the notches 23. The lever 24 is controlled by the arn'iature of the relay 25 in such a manner that, when said relay is energized, the lever is withdrawn from the cam so as to unlock the shaft 19. The speed of rotation of the shaft 19, and therefore the speed of the plunger shaft 18, is controlled through the medium of a suitable governor 26. Associated with the master switch there is a relay 27 the springs of Which, upon being operated, are locked in their operated positions by the engagement of the spring 28 with a detent on the under side of the spring 29. The springs of the relay 27 are unlocked by the arm 30 when the shaft 19 reaches the limit of its travel in one direction. When the shaft 18 reaches the limit of its travel in the other direction, the arm 31 forces the spring-32 into engagement with the spring-33. The master switch is also provided with a bank of contacts, comprising a common segment 34 and an individual contact a for each of the trunklines to which the switches C controlled by the master switch have access. A wiper 35 keeps the common segment 34 in electrical contact with the individual contact a corresponding t the trunk line before which the plungers of the idle line switches are resting. In general, the operation of the master switch is as follows: Whenever a line switch whose plunger is in engagement with the plunger shaft 18 is operated to seize a trunk line, the relay 25 is energized'to unlock the shaft 19. The spring 20 thereupon begins to r0- tate said shaft to cause the plunger shaft to move the idle plnngers away from the trunk line just seized and onto an idle trunk line.

When the idle trunk line is reached, the relay 25 deenergizcs and again. locks the plunger shaft. When the plungers in their operalion puss beyond the last trunk line, the arm 31 forces the spring 32 into contact with the spring 33, whereupon the relay 27 is energized and closes the circuit of the solenoid 21. The solenoid, upon energizing, rotates the shaft 19 bar-k to its initial position so as to bring all the plungcrs which are in engagement with the plunger shaft back to a position opposite the first trunk line and to restore the tension to the spring 20. When the plunger shaft reaches its initial position, the arm 30 unlocks the springs of the relay 27. which permits thesolcnoid to deiinergize and the plunger shaft to come to rest. The master switches D 1) and D are all similar to the master switch I).

Between the master switches D and D (Fig. 1 there is shown a device L the purpose of which will be described hereinafter. This device comprises a set of contacts b, a common segment 37 and a wiper 38. The wiper 38 is adapted to be rotated over the contarts f) step by step by a motor magnet 39. The magnet 40 isa retaining magnet and, while energized, is adapted'to maintain the wiper 38in any advanced position. The springs 41 are separatedbyithe wiper 38 when it engages the last contact I).

The operators cord circuit 0 is provided with the usualanswering and calling supervisory signals 12 and-4&3 and the necessary relays for controlling the same. The donble-wound relay 44 is bridged across the answering end of the cord through the springs of a reversing relay 45. The ringing key 46, when depressed, becomes'loeked in its operated position, but may be unlocked by the energization of the magnet 4.7. The interrupter devices 48 and 49 are adapted to alternately connect the battery B and the ringing current generator 50 with the relay 47.

The substation A is shown provided at the central oflice with acall register-osmoter 51 which is controlled by a doublewound magnet 52. The windings of the magnet 52 are so proportioned that it requires the energization of both windings in ihe same direction. to attract the armature, said armature being unaffected by the-energization of either winding alone. or bythe cnergization of the two windings in opposition to each other.

Referring to Fig. 3, it will be seen that the line switch C is slightly different from the line switch C (Fig. 1) in that it has no armatures corresponding to the line armature 219 and the cut-off armature 218 shown in Fig. 1, these armatures in the switch 0 being controlled by separate relays 53 and 54. The relays 53 and 54 correspond to the usual manual system. The line of the substation A is provided with a central office meter 55 which is controlled by a single-wound magnet 56. The operators cord circuit 0, as shown, differs somewhat from the cord 0 shown in Fig. 1, which difference will be readily understood from the description which is to follow. Allotted to the cord circuit 0 there are two call registers or meters 57 and 58. The meter 58 is adaptedto register all calls which are made throughthe medium of the cord (Y, while the meter 57 registers the successful callsthat is, the calls which are actually answered by the called subscriber.

Throughout the drawings there is shown a plurality of batteries B, B and B for furnishing current for operating the central ofiice rel ays and switches. It will, of course, be understood that in practice these might be one and the same battery, but for convenience of illustration they are shown as separate batteries.

Having given a general description of the apparatus, it will now he explained in detail how the calling subscriber at the substation A may obtain connection with the subscriber at the called substation A As is well known, the plunger of the line switch G, when idle, is always maintained opposite the terminal of an idletrunk line. When the calling subscriber removes his receiver preparatory to makin a call, the closure of the hook switch 4 wit its contact completes a bridge across the calling line through the transmitter and receiver of the calling substation, whereupon the line Winding 59 of the switch C becomes energized. The winding 59, upon energizing, attracts the armature 219, whereby the circuit of the operating winding 60 is closed. The winding 60, upon energizing, attracts the plunger arm 7 and the cut-off armature 218. The armature 218 operates to disconnect. the line winding 59 from the line, while the plunger arm 1 causes the plunger to be thrust into the group of contact springs forming the terminal of the trunk line before which it is being held and forces the springs 9 and 11, 13 and 15 into contact with the springs 10, 12, 14 and 16, respectively, as shown. The engagement of the springs 9 and 11 with the springs 10 and 12, respectively, extends the line connection over the trunk conductors 62 and 63 to the switch C The engagement of the springs 15 and 16 of the switch C completes a circuit extending from ground G through said springs 15 and 16, winding 64 of the switch C and the springs 65, 66, relay 67, back contact of the armature 68, springs 69 of the relay 70 in the master switch D and through the contact 71 to the battery lead 72, thence through battery B to ground G. The winding 64, upon energizing, attracts its plunger arm 72, which operates in the same manner as the plunger arm of the switch C to extend the line con ncction over the trunk conductors 73 and 74 to the cord 0. When the plunger arm 72 is attracted it also forces the spring 75 into engagement with the spring and the spring 65 out of engagement with the spring 66, whereby the operating winding 64 is connected to battery directly through the high resistance holding winding 76 to reduce the current consumption while the switch is being held in its operated position. When the connection is extended to the cord 0 by the secondary switch C, the relay 44 in the cord becomes energized over a circuit extending from ground (i through the upper winding of said relay, back contact of the spring 77, trunk conductors- 74 and 62, thence through the substation A and back over the other side of the line through the left-hand winding of the meter magnet 52, trunk conductors 63 and 73, back contact of the spring 76 and the lower winding of the relay 4-1 to the battery lead 72. The relay 44, upon energizing, closes the circuit of the lamp 42, which circuit extends from ground G through the back contact of the spring 7 8 and the front contact of the sprin 79 and through said lamp to the battery lead. The closure of the contact 80, upon the energizetion of the relay 44, completes a circuit extending from ground G through said contact 80, relay 81, springs 82 and 83, 14 and 13 and the holding winding 84 of the switch to the battery lead 72 for the purpose of maintaining the switch C in its operated position after the line winding 59 has deenergized and opened the circuit of the operating winding 60. During the interval which might elapse between the time when the line winding is deiinergized and the time when the relay 44 of the cord has operated to close the circuit of the winding 84 of the switch C, as above described, said winding is energized over a circuit extending from ground G through its own bank contacts 15 and 16, contact 85 of the relay 67, springs 13 and 14 and the winding 84 to the battery lead. The relay 67 is energized in series with the operating winding of the line switch C and, being a slow acting relay, re mains in its energized position for a short time after the switch C has operated. The relay 81, which is included in the circuit of the holdin winding 84 of the switch 0, is energized in series with said winding, but has no particular function at this time. The purpose of this relay will be fully described hereinafter.

When the springs 15 and 16 of the switch O are forced into contact upon the operation of said switch, a circuit is closed extending from ground G through the springs 15 and 16, contact point 86 (which is assumed to correspond to the trunk line leading to the switch C wiper 35 (which is assumed to be standing on the contact 86 at the time), common segment 34 and the relay 87 to the battery lead 72. The relay 87, upon energizing, closes the circuit of the relay 25, which operates to unlock the plunger shaft and permit the plungers to be moved to an idle trunk line, as hereinbefore described. When the plungers reach a position opposite an idle trunk line, the wiper 35 engages a non-grounded contact and the relay 87 dei nergizes, permitting the relay 25 to in turn deiinergize to bring the master switch to rest. During the time the master switch is operating, the operative windingsof all the line switches C which it controls are disconnected from the battery lead by the separation of the springs 88 of the relay 25, so that no line switch can be operated while its plungers are in motion.

When the bank springs 89 and 90 are forced into contact upon the operation of the secondary switch the master switch I) operates in the same manner as explained for the master switch D to advance the plunge-rs of the idle secondary switches to an idle trunk line.

Upon observing the signal of the lamp 42, the operator at the cord 0 operates the listening key K to connect her talking set with the line and inquires the number of the] desired station in the usual manner. Upon learning the number of the station desired, the operator inserts the plug P (Fig. 2) into the multiple jack of the called line and depresses the ringing key 46. Upon the insertion of the plug into the jack a circuit is closed extending from grounds G and G through the relays 91 and 92 in multiple, thence through the third conductor and through the cut-off winding 93 of the called subscribers switch C to the battery lead 72. The winding 93, upon energizing, attracts the cut-off armature 94 to disconncct the switch from the line, but is not strong enough to attract the plunger arm 95 from its normal position. The relay 9L upon energizing, closes the contact 96 in the talking circuit and shifts the connection of the ground G from the front contact spring 200 of the relay 44 to the back contact spring 201 of said relay, whereby the circuit of the lamp 42 is broken. The relay 92, upon energizing, closes the circuit of the answering supervisory lamp 43 at the contact 97. The depression of the ringing key 46 opens the talking circuit between the calling and the called substations, grounds one side of the line at G and connects the other side of the called line through the relay 47 and the interrupters 48 and 49 to the grounded battery B and the ringing current generator 50. Through the medium of the interrupters the generator and battery are alternately connected with the line, whereby the called subscriber is rung periodically. When the called subscriber removes his receiver, or as soon thereafter as the interrupter 48 con nccts battery B with the line, the magnet 47 is energized and unlocks the key 46, whereby said key is restored to its normal position to disconnect the ringing current from the called line and to restore the talklng connection. The called substation is provided with talking current over a circuit which extends from ground (Jl through the relay 98, springs 99 of the ringing key, ring conductors of the plug 1 and the jack J thence through the substation A and back over the other side of the line, tip conductors of the jack J 2 and the plug P, springs 100 of the ringing key 46, springs 96 and the relay 101 to the battery lead 72. The relay 98, upon energizing, breaks the circuit of the lamp 43 to signify to the oper ator that the called subscriber has answered.

The "function of the relay 101 is as follows: It will he remembered that when the connection was first extended to the cord 0 by the switches C and (l the calling substation was provided with talking current through the two windings of the relay 44 in the cord, which current also flows through the left-,hand windingof the meter magnet 52 at the switch C. This current has no efiect upon the magnetyhowever, as it is at this time opposed by current flowing in the right-hand winding of said magnet, the path of this latter current being from ground G at the cord 0 over the circuit traced for the winding 84 otthe switch C to the spring 13, thence through the right-hand winding of the magnet 52 and the contact 102 (which is closed upon the o iieration of the plunger arm 7) to the battery lead 72. When the relay 101 in the cord is energized upon the response of the called subscriber, as explained above, it closes the circuit of the relay 45. The relay 45, upon energizing, transposes the connections between the winding of the relay 44 and the trunk conductors 73 and 74, as a result of which the direction of the current flowingin the calling line, and consequently in the left-hand winding of the meter magnet 52, is reversed. This reversal of the current in the left-hand winding of the meter magnet causes the two windings to now assist each other, and as a consequence the armature of'said magnet is attracted and operates to register the call upon the meter 51. The magnet 52, upon energizing, also closes the contact 103, whereby the left-hand winding of said magnet is short-circuited. The magnet then remains held in its operated position by the right-hand winding alone, which, although it is not strong enough to operate the armature, is strong enough to hold it in its operated position. The short-circuiting of the left-hand winding renders the meter magnet inoperative to any other changes in the line current, so that the meter is incapable of being operated more than once, even though the called subscriber should move his receiver hook up and down a number of times and thereby re verse the current in the calling line several times.

Upon the completion of the conversation the operator is given the usual disconnect signals by the hanging up oi? the receivers at the calling and called substations in the following manner: Upon the hanging up of the receiver at the called substation A the relays 98 and 101 of the cord are deprived of current. The relay 98, upon deiinergizing, closes the circuit of the calling supervisory lamp 43. Upon hanging up his receiver the calling subscriber destroys the energizing circuit of the relay 4% in the cord. The relay 4-1. upon dei nergiziug, pluses the circuit of the lamp 42, said circuit extending from ground G through the front. contact of the spring; 78 and the back contact of the spring 79 and the lamp 4:2 to the battery lead 72. Upon noting the simultaneous glowing of the lamps 42 and 43 the operator removes the plug P from the jack J Upon. the re moral of the plug the circuit of the relays 91 and 92 in the cord is broken. The relay 9], upon deenergizing, breaks the circuit of the lamp 42, and the relay 92, upon deenergizing, breaks the circuit of the lamp 43 and also the circuit of the holding winding 8 of the switch C. The Winding 84-, upon dcenergizing, permits the plunger of said switch to restore to its normal position, whereupon the holding circuit of the switch C is broken at the springs 15 and 16, and this switch also restores to its normal position, thereby leaving all the apparatus which was employed in the call in a normal position in readiness for another call. Of course, the circuit of the rigl'it-hz-rnd winding of the meter magnet 52 is broken at the same time the circuit of the winding 84- of the switch C is broken, and said magnet accord ingly deenergizes.

Having given a description of the manner in which a connection is established and released, the pur 3058 and mode of operation of the device J shown between the master switches D and D will now be explained. As is well known, the type of switches to which the switches C and C belong are so arranged that after a switch has been operated and released, its plunger does not immediately return into locking engagement with the plunger shaft, but remains in front of the bank terminal from which it was last disengaged until the master switch, by subsequent operations, brings the plunger shaft back to the position in which it was standing when said switch was operated. In the system described herein, there are usually more secondary switches C in a group than there are trunk lines leading out of said group. It will thus be seen that all of the trunk lines leading out of a secondary group may become busy while there still are idle trunk lines leading from the primary switches into the busy secondary group, and it may be that in some primary group there may be a plunger disconnected from its plunger shaft and standing in front of one of these idle trunk lines leading into the busy secondary group. It is the function of the device L to cause the rimary master switches D to operate to pick up all their idle plungers and bring them into locking engagement with their plunger shaft whenever all of the trunk lines leading out of the secondary group become busy. This is accomplished as follows: It will be remembered that the relay 81 was energized when connection was extended to the cord 0. There is one such relay for every trunk line leading to the manual board. There are shown herein the relays 81, 81 and 81 belonging to the first, second and last trunk lines of the group which is accessible by the group of switches to which the switch C belongs. The contacts of these relays are all connected in series, so that when all the trunk lines of the group become busy, and consequently when all the relays 81, 81 and 81 become energized, a circuit is closed from ground G through the relay 105. The relay 105, upon energizing, closes the circuit of the relay 106 and, by opening the contact 71, disconnects the battery from the master switch D to prevent it from operating. The relay 106, upon energizing, disconnects the battery from the operating winding 64 of all the idle secondary switches C of the group and extends a guarding potential from ground G through the last winding 64' to the corresponding contacts a in the master switch banks of the primary master switches D. The relay 105, upon energizing, also closes a circuit for the holding magnet 39 of the device L by closing the contact 107, grounds the common segment 37 and closes a circuit through the operating winding 40, said circuit extending from ground G through the contact 107, contact 108, relay 109, contact 41 and the magnet 40 to the battery lead 72. The magnet 40 thereupon energizes and rotates the wiper 38 one step, while at the same time the relay 109 energizes to close the circuit of the relay 110. The relay 110, upon energizing, breaks the circuit of the magnet 10 and the relay 109. The relay 109, u on deenergizing, breaks the circuit of the re ay 110, which in turn, upon de'einergizing, again closes the circuit of the magnet 40 to cause the Wiper 38 to be advanced a second step. It will, therefore, be

seen that upon the closure of the contact 107 by the relay 105 the magnet 40 begins to operate to automatically advance the wiper 38 step by step, said wiper remaining on each contact during the time which it takes for the relays 109 and 110 to decnergize, and since these relays are both slow acting this time is of some little length. The contacts I), which are engaged by the wi mi 38, are connected with the starting re ays 87 of the respective primary muster switches D, so that as the wiper 38 passes over its contacts it closes the circuits of the starting relays of the different primary master switches D in succession, and maintains said circuits closed long enough to permit each master switch to cause its plunger shaft to make at least one complete oscillatory movement, whereby all the plungers are picked up and brought-into locking engagement with their plunger shaft. If desired the wiper 38 may be caused to engage a plurality of contacts at each step, so as to cause a plurality of the primary master switches to be operated at one time. After the wiper 38 has passed beyond the last contact, it opens the circuit of the rotary magnet 40 at the springs 41 and, therefore, comes to rest. When one of the. trunk lines leading out of the secondary group becomes idle, the relay 105 denergizes andbreaks the circuit of the holding magnet 39, whereupon the wiper 38 returns to its normal position.

The operation of'the apparatus shown in Figs. 3 and 1,'through the medium of which connection is extended from the substation A to the called substation A, is, in general. as follows: The operations of the switches C and C and the master switches D and I) being essentially the same as described in connection with Fig. 1, it is not thought necessary to explain the same in detail. Upon the removal of the receiver at the. callin substation A, the line relay 53 is energized and closes the circuit of the operating winding 111 of the switch C, whereupon the connection is extended to the switch (3. which in turn is operated to extend the connection to the operators cord 0. The calling substation is thereupon provided with talking current over a circuit extending from ground G through one winding of the repeatin coil 112, trunk conductors 113 and 114, t ence through the substation A and back over the other side of the line, over the trunk conductors 115 and 116 and through the relay 117 and a winding of the repeating coil 112 to the battery lead 120, thence through the battery B" to ground. The relay 117, upon energizing, completes aholding circuit for the switches C and C, which circuit extends from round G through the front contact of 518 armature 121, relay 122 (which corresponds in function to the relay 81" in Fig. 1), contact 222, windings of the switch C and the contact 123 and windings of the switch C in multiple therewith to the battery lead 120. Also, upon completion of the connection with the cord l) a circuit is closed eX- tendin from ground (1' at the cord through the rclhy 124, thence through the contacts 125 and 1213 and through the windings of the meter magnet 56 and the cut-oil relay 54- in multiphto the huttery lead I20. The cutsol'l" relay is energized by this current and operates to disconnccl the line relay from the line, while the meter magnet 51' does not receive sullicicnt current in series with the relay 124- to he operatively energized. The relay 124 in the cord, upon energizing, completes the circuit of the lamp 127, which circuit extends from ground G through the back contact of the armature 128 and the from contact of the armature 1.29 and the lamp 127 to the battery lead. The operator, upon noting the signal displayed by lhc lamp 127* inquires oi the calling subscl-ilu-r the number of the line desired and then lllrvlls 1hr plug 1" (Fig. ll into a mul tiplc jucl: J o the desired line. Upon th insertion of the plug 1" into the jack J" a circu t i closed from grounds i and (P in The cord through the relays 131) and 131 in multiple, thence through the third conductors of the plug P and the jack J and through the cut-off relay 132 and the meter magnet 133 of the called line in multiple to the battery lead 120. The relays 130, 131 and 132 are all operated over this circuit, the meter magnet 133, however, not receiving suflicient current to be operatively energized. The relay 130 in the cord, upon energizing. opens the circuit of the lamp 127, while the relay 131, upon energizing, closes the contact 133 in the talking circuit and also closes a circuit extending from ground G through the contact 135, contact 136 and the relay 137 lo battery. The relay 137, upon energizing, closes a circuit extending from ground G through the contacts 135 and 138 and the meter magnet 139 to the battery lead 120. A second circuit is closed. extending from ground G through the contacts 135 and 140, lamp 141 and the relay 142 to the battery lead 120. The lamp 141 is lighted and the relay 142 energized over this latter circuit. The relay M2, upon energizing, forms a locking circuit for itself through the contact 14-3, independent of the contacts of the relay 137, and breaks the circuit of the relay 137 at the contact 136. The relay 137, which is slightly slow acting, deenergizes shortly and breaks the circuit of the meter magnet 139. It will thus be seen that as a result of the energization of the relay 131 upon the insertion of the plug P into the jack J, the calling supervisory lamp 141 is lighted and a single impulse is transmitted through the meter magnet 139 to register the call on the totalizing meter 58. Since the relay 142, upon energizing, becomes locked up through its own contact, no more impulses can be transmitted through the meter magnet 139 until the plug has been withdrawn from the jack.

The called subscriber is signaled through the medium of the ringing key 144 in the same manner as described in connection with Fig. 1. Upon the response of the called subscriber the called substation is provided with talking current from the battery B through the two windings of the repeating coil 1.12 and the answering supervisory relay 145 in the usual manner. The relay 145, upon energizing, closes a shunt around the lamp 141 through the relay 146, said shunt extending from ground G through the contacts 135 and 147 and the relay 146 to the relay 142. The relay 146 receives enough current in this circuit to be operatively energized and shunts enough current away from the lamp 141 to cause it to be eX- tinguished to signify to the operator that the called subscriber has answered. The relay 146, upon energizing, closes an energizing circuit through the relay 148 by way of the contacts 135, 149 and 150. The relay 148, upon energizing, closes a circuit through the relay 152 by way of the contacts 135 and 153. The relay 152, upon energizing, closes a locking circuit for itself at the contact 154 and breaks the circuit of the relay 148, which, being slow acting, after a short interval, deenergizes. In its energized position the relay 148 closes a circuit extending from ground G15 through the battery B relay 156, contact 157, thence back through the contacts 125 and 126 of the switches C and C and through the meter magnet 56 and the cut-ofl' relay 54 to the battery lead 120, thence through the battery B to ground. It will be seen that inthis circuit the batteries B and B are connected in series, whereby the current in the meter magnet 56 is increased sufliciently to cause said magnet to operate the meter. At the cord 0 the energization of the relay 156 serves to close the circuit of the meter magnet 158, whereby the effective call meter is operated once. Since the energization of the relay 148 is only momentary, the relay 156 is energized only for an instant and the current in the subscribers meter magnet 56 is increased only momentarily. The meter magnet 56, however, does not restore to normal position upon the return of its energiz ing current to its original strength, however, as said magnet is preferably arranged so that, although it cannot be operated by its original current, it may be maintained in its operated position by said current. Since the relay 152 in the cord, upon being once energized, becomes looked through its own contact, the relay 148 cannot cause more than a single impulse to be transmitted through the meter magnets 56 and 158 for each call.

Upon the completion of the conversation the operator is given the usual disconnect signals upon the hanging up of the receivers at the calling and called substations. The hanging up of the receivers permits the relays 1-1-5 and 11? to deiincrgizc. The relay 145, upon deiinergizing, removes the shunt from around the lamp 141 and allows it to become lighted again. The relay 117, upon deenergizing, closes the circuit of the lamp 127 by way of the back contacts of the armature 121 and the front contact of the arma ture of the relay 124. Upon the removal of the plug from the jack by the operator all the relays in the cord circuit which were locked up as a result of the insertion of the plug in the jack, or upon the response of the called subscriber. become deiinergized, and the relay 130. upon (lcenergizing, destroys the holding circuit of the switches C and C, allowing them to be restored to normal position. wliereupon the relay 124 in the holding circuit becomes decnergized and ex" tinguishes the; lamp 127.

While I have illustrated my invention in connection with a semi-automatic telephone system of a particular type, and in which certain ty es of automatic switches are employed, it 1s, of course, to be understood that my invention is not limited to use in connection with such systems, but that it is capable of use in connection with many other semiautomatic systems in which various types of automatic switches are employed.

What I claim as my invention is 1. In a telephone system, a calling and a called subscribers line, a manual operators cord circuit for establishing connection with the called line, primary and secondary l'runkselecting switchea for establishing connection from a calling line to said cord circuit, said secondary switches operating in response to the operation of said rimary switches, a meter on said calling line, and means for automatically operating said meter upon the response of the called suhscriber.

2. In a telephone system, a plurality of subscribers lines, a plurality of operators cord circuits for connecting with a called subscribers line, a trunk-selecting switch on each of said subscribers lines, a master switch for controlling a group of said trunk switches for reselecting an idle cord, a meter for registering the calls, and means for automatically operating said meter upon the response of the called subscriber.

3. in a. telephone system, a plurality of subscribers lines, a plurality of operators cord circuits the connecting with a called subscribers line, a primary trunking switch on each subscribers line, a secondary trunking switch, a master switch for controllin a group of said primary trunking switc es for automatically selecting trunk extending to said secondary trunking switch, means for then operating said second trunking switch for automatically selecting an idle cord, a meter for registering calls, and means for automatically operating, said meter upon the response of the called subscriber.

4.. In a telephone system, a plurality of subscribers lines, automatic means for establishing a talking circuit between two of said lines, a meter for registering the calls, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of such'connection, and means for transmitting a strengthened impulse through said magnet over a circuit exclusive of the talking circuit to operate the same by the called subscriber.

5. In a telephone system, a plurality of subscribers lines, automatic means for establishing a talking circuit between two of said lines, a meter for registering the calls, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of such connection, and means for automatically transmitting a strengthened impulse through said magnet over a circuit exclusive of the talking circuit to operate the same by the called subscriber.

6. In a telephone system, a calling and a called subscribers line, means including automatic selecting switches and a manual operators cord circuit for establishing a talking circuit between said lines, a meter for registering calls, an operating magnet therefor, means for transmitting current of one strength through said magnet over a circuit independent of said talking circuit during the establishment of said connection between said subscribers lines, and means for transmitting a strengthened impulse through said magnet to operate the same by the called subscriber.

7. In a telephone system, a calling and a called subscribers line, a manual operators cord circuit for connecting with thecalled line, a trunk-selecting switch on the calling line for selecting an idle operators cord, a meter for re 'stering calls, an operating magnet there or, means for transmitting current of one strength through said magnet during the establishment of said connection between said subscribers lines, and means for transmitting a strengthened impulse through said magnet to operate the same by the called subscriber.

8. In a telephone system, a calling and a called subscribers line, a manual operators cord circuit for establishing connection with the called line, primary and secondary trunk-selecting switches for establishing connection from a calling line to said cord circuit, a meter on said calling line, an operating magnet therefor, means for transmitting current ofwone strength through said magnet during the establishment of said connection between said subscribers lll'lGS,El,lld means for transmitting a strengthened impulse through said magnet to operate the same by the called subscriber.

9. In a telephone system, a plurality of subscribers lines, a plurality oi. operators cord circuits for connecting with a called subscribefis line, a trunk-selecting switch on each of said subscribers lines, a master switch for controlling a group of said trunk switches for preselccting an idle cord, a meter for registering the calls, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of said connection between said subscribers lines, and means for transmitting a strengthened impulse through said magnet to operate the same by the called subscriber.

10. In a telephone system, a plurality of subscribers lines, a plurality of operators ('nid circuits for connecting with a called subscribers line. a trunking switch on each subscribefs line, a master switch for controlling a group of said trunking switches for automatically selecting a trunk extending to a secondary trunking switch, means for then operating said second trunking switch for automatically selecting an idle cord, a meter for registering calls, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of said connection between said subscribers lines, and means for transmitting a strengthened impulse through said magnet to operate the same by the called subscriber.

11. In a telephone system, a calling and a called subscribcrs line, means including automatic selecting switches and a manual operators cord circuit for establishing a talking circuit between said lines, a meter for registering calls, a magnet for operating said meter each time the said magnet is energized, means whereby the response of the called subscriber causes a momentary impulse of current to be transmitted throu h said meter over a circuit independent of said talking circuit to operate the same, and means for rendering said impulse-transmitting device inoperative after one impulse is transmitted.

12. In a telephone system, a calling and a called subseribers llne, a manual operators cord circuit for connecting with the called line, a trunk-selecting switch individual to the calling line for selecting an idle operators cord, a meter for registering calls, a magnet for operating said meter each time the said magnet is energized, means whereby the response of the called subscriber causes a momentary impulseof current to be transmitted through said meter to operate the same, and means for rendering said impulse-transmitting device inoperative after one impulse is transmitted.

1.3. In a telephone system, a calling and a called subscribefis line, a manual operators cord circuit for establishing connection with the called line, primary and secondary trunk-selecting switches for establishing connection from a calling line of said cord circuit, a meter on said calling line, a magnet for operating said meter each time the said magnet is energized; means whereby the response of the called subscriber causes a momentary impulse of current to be transmitted through said meter to operate the same, and means for rendering said impulse-transmitting device inoperative after one impulse is transmitted.

14. In a telephone system, a plurality of subscribers" lines, a plurality of operators cord circuits for connecting with a called subscriber-s line, a trunk-selecting switch on each of said subscribers lines, a master switch. for controlling a group of said trunk switches for prcselccting an idle cord, a meter for registering the calls, means whereby the response of the called subseriber causes a momentary impulse of current to be transmitted through said meter to operate the same, and means for rendering said impulse-transmitting device inoperative after one impulse is transmitted.

15. In a telephone system, a plurality of subscribers lines, a plurality of operators cord circuits for connecting with a called subscribers line, a trunking switch on each subscriber's line, a master switch for controlling a group of said trunking switches for automatically selecting a trunk extending to a secondary trunking switch, means for then operating said second trunking switch for automatically selectin an idle cord, a meter for registering calls, means whereby the response of the called subscriber causes a momentary impulse of current to be transmitted through said meter to operate the same, and means for rendering said impnlse-transmitting device inoperative after one impulse is transmitted.

16. In a telephone system, a plurality of subscribers lines, automatic means for establishing a talking circuit between two of said lines, a meter for registering said connections, an operating magnet therefor, means for transn'iitting current of one strength through said magnet. over a circuit independent of said talking circuit during the establishment of such connection, means for transmitting a momentary strengthened impulse of current through said magnet to operate the same upon the response of the called subscriber, and means for renderin said strengthened inipulsc-transmitting means inoperative after one impulse is transmitted.

17. In a telephone system, a plurality of subscribers lines, automatic means for establishing a talking circuit between two of said lines, a meter for registering said connections, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of such connection over a circuit independent of said talking circuit, means for automatically transmitting a momentary strengthened impulse of current through said magnet to operate the same upon the response of the called subscriber, and means for rendering said strengthened impalso-transmitting means inoperative after one impulse is transmitted.

18. Inatelephone system, a calling and a called subscribers line, a manual operators cord circuit for connecting with the called line, primary and secondary trunk select ing switches controlled from the calling line for selecting an idle operators cord, a release circuit for releasing said switch, a meter comprising a magnet for registering calls, means for automatically operating said meter upon the response of the called subscriber, and another magnet for closing the release circuit.

19. In a telephone system, calling and called subscribers lines, a manual operators cord circuit for establishing connection with the called line, primary and secondary trunk selecting switches controlled by the calling line for establishing connection to the cord circuit, a meter on said calling line and means for automatically operating said n'ieter upon the response of the called subscribe-r.

:20. In a telephone system, a plurality of subscribers lines, means controlled over two sides of a calling line in series for establishing a talking circuit between two of said lines, a meter for registering said connection, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of such connection over a circuit independent of said talkin. circuit, and means controlled by the cello subscriber for raising the voltage through said magnet to operate the same upon the response of the called subscriber.

21. In a telephone system, a plurality of subscribers lines, means controlled over two sides of a calling line in series for establishing a talking circuit between two of said lines, a meter for registering said connection, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of such connection over a circuit independent of said talking circuit, and means for raising the voltage momentarily through said magnet to operate the same by the called subscriber.

22. In an automatic telephone system, a

plurality of subscribers lines, means controlled over two sides of a calling line in series for establishing a talking circuit between two of said lines, a meter for registering said connection, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of such connection over a circuit independently of said talking circuit, and means for automatically raising the voltage throu h said magnet to operate the same upon tie response of the called subscriber.

23. In n automatic telephone system, a plurality of subscribers lines, means controlled over two sides of a calling line in series for establishing a talking circuit between two of said lines, a meter for registering said connection, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of such connection over a circuit independent of said talking circuit, and means for automatically raising the voltage momentarily through said magnet to operate the same upon the response of the called subscriber.

24. In telephone system, a calling and a called subscribers line, means including automatic selecting switches and a manual operators cord circuit for establishing a talking circuit between said lines, a meter for registering calls, an operating magnet therefor, means for transmitting current of one stren h through said ma net over a circuit in ependent of said taliing circuit during the establishment of said connection between said subscribers lines, and means for transmitting an impulse of strengthened voltage through said magnet to operate the same b Y the called subscriber.

25. In a telep one system, a calling and a called subscribers line, a manual operators cord circuit for connecting with the called line, a trunk-selecting switch on the calling line for selecting an idle o erators cord, a meter for re -staring cal s, an operating magnet there or, means for transmitting current of one strength through said magnet during the establishment of said connection between said subscribers lines, and means for transmitting an im ulse of strengthened voltage through sai ma et to operate the same by the called subscriber.

26. In a telephone system, a calling and a called subscribers line,amam1aloperators cord circuit for establishing connection with the called line, primary and secondary trunk-selecting switches for establishing connection from a calling line to said cor circuit, a meter on said calling line, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of said connection between said subscribers lines, and means for transmitting an impulse of strengthened voltage through said magnet to operate the same by the called subscriber.

27. In a telephone system, a plurality of subscribers lines, a plurality of operators cord circuits for connecting with a called subsrribefis line, a trunk-selecting switch on each of said subscribers lines, a master switch for controlling a group of said trunk switches for preselecting an idle cord, a meter for registering the calls, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of said connection between said subscribers lines, and means for transmitting an impulse of strengthened voltage through said magnet to operate the same by the called subscriber.

28. In a telephone system, a plurality of subscribers lines, a plurality of operators cord circuits for connecting with a. called subscribcrs line, a trunking switch on each subscribers line, a master switch for controlling a group of said trunking switches for automatically selecting a trunk cxtending to a secondary trunking switch, means for then operating said second trunking switch for automatically selecting an idle cord, a meter for registering calls, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of said connection between said subscribers lines, and means for transmitting an impulse of strengthened voltage through said magnet to operate the same by the called subscriber.

29. In a telephone system, a plurality of subscribers lines, automatic means for establishing a talkin circuit between two of said lines, a meter or registerin said connec tions, an operating magnet t erefor, means for transmitting current of one strength through said magnet over a circuit independent of the talking circuit during the establishment of such connection, means for transmitting a strengthened impulse of current through said magnet to operate the same upon the response of the called subscriber, and means for rendering said strengthened impulse-transmitting means inoperative after one impulse is transmitted.

30. In a telephone system, a plurality of subscribers lines, automatic means for establishing a talkin circuit between two of said lines, a meter or registering said connections, an operating magnet therefor, means for transmitting current of one strength through said magnet over acircuit independent of the talking circuit during the establishment of such connection, means for automatically transmittin a strengthened impulse of current throng said magnet to operate the same upon the response of the called subscriber, and means for rendering said strengthened impulse-transmitting means inoperative after one impulse is transmitted.

31. In a telephone system, a calling and a called subscribers line, means including primary and secondary trunk selecting switches and a manual operators cord circuit for establishing a connection between said lines, said secondary switches operating in response to the operation of said primary switches, a meter for registering calls, means whereby the response of a called subscriber causes a momentary impulse of current to be transmitted through said meter to operate the same, and means for rendering said impulse transmitting device inoperative after one impulse is transmitted.

32. In a telephone system, a calling and a called subscribers line, a manual operators cord circuit for connecting with the called line, primary and secondary trunk selecting switches for selecting an idle operators cord circuit, said secondary switches operating in response to the operation of said primary switches, a meter for registering calls, means whereby the response of the called subscriber causes a momentary impulse of current to be transmitted through said meter to operate the same, and means for rendering said impulse transmitting device inoperative after one impulse is transmitted.

33. In a telephone system, a calling and a called subscribers line, means including automatic selecting switches and a manual operators cord circuit for establishing a tal ing circuit between said lines, a meter for registering calls, means including a relay whereby the response of the called subscriber causes a momentary impulse of current to be transmitted throu h said meter over a circuit independent 0 said talking circuit to operate the same, and means for rendering the said relay inoperative after one impulse is transmitted.

34. In a telephone system, a calling and a called subscribers line, a manual operators cord circuit for connecting with the called line, a trunk selecting switch on the calling line for selecting an idle operators cord circuit, a meter for registering calls, means including a rela whereby the response of the called subscri er causes a momentary impulse of current to be transmitted through said meter to operate the same and means for rendering said relay inoperative after one impulse is transmitted.

35. In 'a telephone system, a temporarily established connection between a calling and called line including a plurality of automatic trunking switches, a circuit independent of the talking conductors and extending through a plurality of said switches, a call register individual to the calling line included in said circuit, and mechanism controlled by the called subscriber for transmitting a momentary current impulse over said circuit to operate said register.

36. In a telephone system, a temporarily established connection between a calling and called line, includin a plurality of automatic trunking switc ies, a circuit independent of the talkin conductors and extending through a plurality of said switches, a call register individual to the calling line included in said circuit, and automatic means actuated upon the response of the called sub scriber for transmitting a momentary current impulse over said circuit to operate said register.

37. In a telephone system, a temporarily established connection between a calling and called. line including a, plurality of automatic trunking switches, a circuit independent of the talking conductors and exlending through a plurality of said switches. a call register individual to the calling line included in said circuit, and automatic electromagnetic means actuated upon the response of the called subscriber for transmitting a momentary current impulse over said circuit to operate said register.

38. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch individual to the calling line, a circuit independent of the talking conductors including a movable contact in said switch, a call register individual to the calling line included in said circuit, and mechanism controlled by the culled subscriber for transmitting a momentary current impulse over said circuit to operate said register.

39. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch individual to the calling line, a circuit independent of the talking conductors including a movable contact in said switch, a call register individual to the calling line included in said circuit, and automatic means actuated upon the response of the called subscriber for transmitting a momentary current impulse over said circuit to operate said register.

40. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch individual to the calling line, a circuit independent of the talking conductors including a movable contact in said switch, a call register individual to the calling line included in said circuit, and electromagnetic automatic means actuated upon the response of the called subscriber for transmittlng a momentary current impulse over said circuit to operate said register.

41. In a telephone system, a temporarily established connection between a calling and a called line including an automatic trunking switch and an operators cord circuit,

a circuit independent of the talking conductors and including a movablc contact of said switch, a call register individual to the calling line included in said circuit, and mechanism controlled by the called subscriber for transmitting a momentary current impulse over said circuit to operate said register.

42. In a telephone system, a temporarily established connection between a calling and a called line including an automatic trunking switch and an operators cord circuit, a circuit independent of the talking conductors and including a movable contact of said switch, a call register individual to the calling line included in said circuit, and automatic means actuated upon in response of the called subscriber for transmitting a momentary current impulse over said circuit to operate said register.

43. In a telephone system, :1 temporarily established connection between a calling and a called line including an automatic trunking switch and an operators cord circuit, a circuit independent of the talking conductors and including a movable contact of said switch, a call register individual to the calling line included in said circuit, and electro' magnetic automatic means actuated upon the response of the called subscriber for transmitting a momentary current impulse over said circuit to o )erate said register.

44. In a telep one s stem, a temporarily established connection etween a calling and called line including a non-numerical automatic trunking switch individual to the calling line, a circuit independent of the talking conductors including a movable contact in said switch, a call register individual to the calling line included in said circuit, and mechanism controlled by the called subscriber for transmittin a momentary cur rent impulse over said circuit to operate said register.

45. In a telephone system, a temporarily established connection between a calling and called line including a non-numerical automatic trunking switch individual to the calling line, a circuit independent of the talking conductors including a movable contact in said switch, a call register individual to the calling line included 1n said circuit, and automatic means actuated upon the response of the called subscriber for transmitting a momentary current impulse over said circuit to operate said register.

46. In a telephone system, a temporarily established connection between a calling and called line including a non-numerical automatic trunking switch individual to the calling line, a circuit independent of the talking conductors including a movable contact in said switch, a call register individual to the calling line included in said circuit, and electromagnetic automatic means actuated upon the response of the called subscriber for transmitting a momentary current impulse over said circuit to operate said register.

47. In a telephone system, a temporarily established connection between a calling and a called line including an automatic trunking switch individual to the calling line, a cut-off relay and a call register for the callmg line, a common circuit for said relay and register including a battery, said register being lrresponsive to normal current flow in said circuit, and mechanism controlled by the response of the called subscriber for increasing the current fioW in said circuit to operate said re ister.

48. In a telep one system, a temporarily established connection between a calling and a called line including an automatic trunking switch individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, and automatic devices for increasing the current flow in said circuit to operate said register prior to conversation over said connection.

49. In a telephone system, a temporarily established connection between a calling and a called line including an automatic trunking switch individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, a second battery, and automatic means for connecting said second battery in series with said first battery in said circuit to increase the current flow therein to operate said register.

50. In a telephone s stem, a temporarily established connection tween a calling and a called line including an automatic trunking switch individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery, said re ister being irresponsive tc normal current ow in said circuit, a second battery, and automatic means controlled by the response of the called subscriber for including said secand battery in said circuit to increase the current flow therein to ope-rate said register.

51. In a telephone s stem, a temporarily established connection etween a calling and a called line including an automatic trunking switch'individual to the calling line, a cut-ofl relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, and automatic devices for momentarily increasing the current flow in said circuit to operate said register.

52. In a telephone system, a temporarily established connection between a calling and a called line includin an automatic trunking switch individua to the calling line, a cut-0H relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register be ing irresponsive to normal current flow in said circuit, and mechanism controlled by the called subscriber for momentarily increasing the current flow in said circuit to operate said register.

53. In a telephone system, a temporarily established connection between a calling and a called line including an automatic trunking switch individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery, said re 'ster being irresponsive to normal current ow in said circuit, and electromagnetic mechanism controlled by the response of the called subscriber for increasing the current flow in said circuit to operate said register.

5-1. In a telephone system, a temporarily established connection between a calling and a called line including an automatic trunking switch individual to the calling line, a cutoff relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, a second battery, and automatic electromagnetic means for connecting said second battery in series with said first battery in said circuit to increase the current flow therein to operate said register.

In a telephone system, a temporarily established connection between a calling and a called line including an automatic trunking switch individual to the calling line, a cutoff relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, a second battery, and electromagnetic automatic means controlled by the response of the called subscriber for including said second battery in said circuit to increase the current flow therein to operate said register.

56. In a telephone system, a temporarily established connection between a calling and a called line including an automatic trunking switch individual to the calling line, a cutoff relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, and electromagnetic mechanism controlled by the called subscriber for momentarily increasing the current flow in said circuit to operate said register.

57. In a telephone s stem, a tem orarily established connection. etween a cal ing and it called line including a plurality of automatic trunking switches, a cut-off relay and a call register for the calling line, a common circuit for said relay and register in cluding a battery and movable contacts in said switches, said register being irresponsive to normal current flow in said circuit, and mechanism controlled by the response of the called subscriber for increasing the current flow in said circuit to operate said register.

58. In a telephone system, a temporarily established connection between a calling and a called line including a plurality of automatic trunking switches, a cut-oil relay and a call register for the calling line, a common circuit for said relay and register including a battery and movable contacts in said switches, said register being irresponsive to normal current flow in said circuit, and automatic devices for increasing the current flow in said circuit to operate said register prior to conversation over said connection.

59. In a telephone system, a temporarily established connection between a calling and a called line including a plurality of automatic trunking switches, a cut-off relay and a call register for the calling line, a coinmon circuit for said relay and register including a battery and movable contacts in said switches, said register being irresponsive to normal current flow in said circuit, a second battery and automatic means for connecting said second battery in series with said first battery in said circuit to increase the current flow therein to operate said register. Y

60. In a telephone system, a temporarily established connection between a calling and a called line including a plurality of automatic trunking switches, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery and movable contacts in said switches, said register being irresponsive to normal current flow in said circuit, a second battery and automatic means controlled by the response of the called subscriber for including said second battery in said circuit to increase the current flow therein to operate said register.

61. In a telephone system, a temporarily established connection between a calling and a called line including a plurality of automatic trunking switches, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery and movable contacts in said switches, said register being irresponsive to normal current flow in said circuit, and automatic devices for momentarily increasing the current flow in said circuit to operate said register.

69- In a telephone system. a temporarily cstablis-zhcd connect ion between a calling and a called line including a plurality of automatic trunking switches, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery and u'iovable contacts in said writches, said register being irresponsire to normal current flow in said circuit, and mechanism controlled by the called subscriber for momentarily increasing the current flow in said circuit to operate said register.

63. In a telephone system, a temporarily established connection between a calling and it called line including a plurality of automatic trunking switches, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery and movable con tacts in said switches, said register being irresponsire to normal current flow in said circuit, and electromagnetic mechanism controlled by the response of the called subscriber for increasing the current flow in said circuit to operate said iegister.

(A. In a telephone system, a temporarily established connection between a calling and a called line including a plurality of automatic trunking switches, a cut-ofi' relay and a call re ister for the calling line, a common circuit for said relay and register including a battery and movable contacts in said switches, said register being irresponsive to normal current flow in said circuit, a second battery and electromagnetic automatic means for connecting said second batv tery in series with said first battery in said circuit to increase the current flow therein to operate said register.

65. In a telephone system, a temporarily established connection between a calling and a called line including a plurality of automatic trunking switches, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery and movable contacts in said switches, said register being irresponsive to normal current flow in said circuit, a. second battery, and electromagnetic automatic means controlled b the response of the called subscriber for including said second battery in said circuit to increase the current flow therein to operate said register.

66. In a telephone system, a temporarily established connection between a calling and a called line including a pluralit automatic trunking switches, a cu-t-o relay and a call 1' star for the calling line, a common circuifior said relay and register including a battery and movable contacts in said switches, said register being irrcspo-nsive to normal current flow in said circuit, and electromagnetic mechanism. controlled by the called subscriber for momentarily increasing the current flue-v in said circuit to operate said register.

(57. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch, a circuit for making the calling line busy including a movable con tact of said switch and a battery, a call register in a branch of said circuit and irresponsive to normal current flow therein, and mechanism controlled by the response of the called subscriber for increasing the current flow in said circuit to operate said register.

68. In a telephone system. a temporarily established connection between -a calling and called line including an automatic trunking switch, a circuit for making the calling line busy including a movable contact of said switch and a battery, a call register in a branch of said circuit and irresponsire to normal current flow therein, and automatic devices for increasing the current flow in said circuit to operate said register prior to conversation over said connection.

69. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch, a circuit for making the calling line busy including a movable contact of said switch and a battery, a call register in a branch of said circuit and irresponsive to normal current flow therein, a second battery, and automatic means for connecting said second battery in series with said first battery in said circuit to increase the current flow therein to operate said re ister.

0. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch, a circuit for making the calling ine busy including a movable contact of said switch and a battery, a call register in a branch of said circuit and irresponsive to normal current flow therein, a second battery, and automatic means con trolled by the response of the called subscriber for including said second battery in said circuit to increase the current flow therein to operate said register.

7-1. In a telephone system, a tel'nporarily established connection between a calling and called line including an automatic trunking switch. a circuit for making the calling line busy including a movable contact of said switch and a battery, a call register in a branch of said circuit and irresponsive to normal current flow therein, and automatic devices for momentarily increasing the eurrent flow in said circuit to operate said register.

72. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch, a circuit for making the calling line busy including a movable contact of said switch and a battery, it call register in a branch of said circuit and irresponsive to normal current flow therein, and mechanism controlled by the called subscriber for momentarily increasing the current How in said circuit to operate said register.

73. Ina telephone system, a temporarily established connection betweenacalling and called line including an automatic trunking switch, a circuit for making the calling line busy including a movable contact of said switch and a battery, a call register in a branch of said circuit and irre'sponsive to normal current flow therein, and electro magnetic mechanism controlled by the response of the called subscriber for increasing the current flow in said circuit to operate said register.

74. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch, a circuit for making the calling line busy including a movable contact of said switch and a battery, a call register in a branch of said circuit and irresponsive to normal current flow therein, a second battery, and electromagnetic automatic means for connecting said second battery in series with said first battery in said circuit to increase the current flow therein to operate said re ister.

75. n a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch, a circuit for making the calling line busy including a movable contact of said switch and a battery, a call register in a branch of said circuit and irresponsive to normal current flow therein, a second battery, and electromagnetic automatic means controlled by the response of the called subscriber for including'said second battery in said circuit to increase the current flow therein to operate said register.

76. In a telephone system, a temporarily established connection between a calling and called line including an automatic trunking switch, a circuit for making the calling line busy including a movable contact of said switch and a battery, a call register in a branch of said circuit and irresponsive to normal current flow therein, and electromagnetic mechanism controlled by the called subscriber for momentarily increasing the current flow in said circuit to operate said register.

77. In a telephone system, a temporarily established connection between a calling and a called line including a non-numerical automatic trunking switch individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battcry, said register being irresponsive to normal current How in said circuit, and mechanism controlled by the response of the called subscriber for increasing the current flow in said circuit to operate said register.

78. In a telephone system, a temporarily established connection between a calling and a called line including a non-numerical au- 'lLU'IIliLlZlG trunking switch individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, and automatic devices for increasing the current flow in said circuit to operate said register prior to conversation over said connection.

79. In a telephone system, a temporarily established connection between a calling and a called line including a non-numerical automatic trunking switch individual to the calling line, a cut-off relay and a call reg ister for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, a second battery, and automatic means for connecting said second battery in series with said first battery in said circuit to increase the current flow therein to operate said register.

80. In a telephone system, a temporarily established connection between a calling and a called line including anon-numerical automatic trunking switch individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, a second battery, and automatic means controlled by the response of the called subscriber for including said second battery in said circuit to increase the current flow therein to operate said register.

81. In a telephone system, a temporarily established connection between a calling and 2. called line including a non-numerical autoi'natic trunking switch individual to the calling line, a cut-off relay and a call register for the calling line. a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, and automatic devices for momentarily increasing the current flow in said circuit to operate said register.

82. I11 a telephone system, a temporarily established connection between a calling and a called line including a non-numerical automatic trunking switch individual to the calling line, a cut-oil relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, and mechanism controlled by the called subscriber for momentarily increasing the current flow in said circuit to operate said register.

83. In a telephone system, a temporarily established connection between a calling and a called line includin a non-numerical automatic trunking switc individual to the call ing line, a cut-oil relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, and electromagnetic mechanism controlled by the response of the called subscriber for increasing the current flow in said circuit to operate said register.

84. In a telephone system, a temporarily established connection between a calling and a called line includin a non-numerical automatic trunking switc 1 individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, a second battery and electromagnetic automatic means for connecting said second battery in series with said first battery in said circuit to increase the current flow therein to operate said register.

85. In a telephone system, a temporarily established connection between a calling and a called line including a non-numerical automatic trunking switch individual to the calling line, a cut-off relay and a call register for the calling line, a common circuit for said relay and register including a battery, said register being irresponsive to normal current flow in said circuit, a second battery, and electromagnetic automatic means controlled by the response of the called subscriber for including said second battery in said circuit to increase the current flow therein to operate said register.

86. In a telephone s stem, a tem 'orarily established connection etween a calling and a called line including a non-numerical antomatic trunking swltch individual to the calling line, a cut-oil relay and a call register for the calling line, a common circuit for said relay and register including a bat tery, said register being irresponsive to normal current flow in said circuit, and electromagnetic'mechanism controlled by the called subscriber for momentarily increasing the current flow in said circuit to operate said register.

87. In a telephone system, a calling and a called subscribers line means includin automatic selecting switches and a manna operators cord circuit for establishing a talking circuit between said lines, ameter for registering calls, an operating magnet therefor, means for transmitting current of one strength through said magnet over a circuit independent of said talking circuit during the establishment of said connection between said lines, and means controlled by the removal of the receiver at the called station for transmitting a strengthened impulse through said magnet to operate the same upon the response of the called subscriber.

88. In a telephone system a plurality of subscribers lines, means controlled over the two sides of a calling line in series for establishing a talking circuit between two of said lines, a meter for registering said connection, an operating magnet therefor, means for transmitting current of one strength through said magnet during the establishment of such connection over a circuit independent of said talking circuit, and means controlled by the removal of the receiver at the called station for raising the voltage through said magnet to operate the same upon the response of the called subscriber.

Signed by me at Chicago, Cook county, Illinois, this 3rd day of August, 1912.

ARTHUR J. RAY, ALEX. E. WALKER.

Copies of tin: patent may be obtained tor nve cent: each, by addressing the "Gomminioner of Patents,

' Washington, D. 0." 

